The document summarizes a study being conducted by the DEP on using ribbed mussels to improve water quality in Jamaica Bay. It discusses: 1) A literature review finding ribbed mussels can filter particles and bacteria from water; 2) Microcosm experiments confirming mussels effectively filter pathogens and their filtration is only temporarily impacted by low salinity; 3) Ongoing mesocosm experiments at a larger scale to test mussel densities and responses to bacteria and freshwater pulses; 4) Plans for an in-situ pilot study deploying 75,000 mussels in Jamaica Bay to monitor their ability to naturally recruit and improve water quality.

1. DEP Ribbed Mussel Study
Jamaica Bay LTCP
Jamaica Bay Task Force Meeting
May 10, 2022
John McLaughlin
Managing Director
Office of Ecosystem Services, Green Infrastructure and Research

2. 2
Agenda
1. Ribbed Mussel Study Overview
2. Literature Review
3. Microcosm Bench-top Experimental Results
4. Mesocosm Lab Testing Experimental Protocol
5. In-Situ Pilot Study Considerations

3. 3
1
Literature
Review
2
Microcosm
Bench-top Testing
3
Mesocosm
Lab Testing
4
In-Situ
Pilot Study
Ribbed Mussel Study Overview
1 2 3 4

4. 4
Literature
Review Intent
Gain further understanding of:
• Filtration capabilities of
Ribbed Mussels
• How Ribbed Mussels have
been used in other studies
to improve water quality
• Using mussels in a sub-tidal
setting
1

5. 5
Literature Review
Conclusions
• Ribbed mussels are capable
of filtering out particles as
small as bacteria (< 1 micron)
from water
• Additional studies
recommended to evaluate
bacterial removal (E. coli and
Entero) via filtration by Ribbed
Mussels
Literature Reference Particle Size
Filtration
Efficiency
Langdon & Newell (1990) < 2 µm 15.8%
Newell & Krambeck (1995) Not specified 30-35%
Riisgard (1988) 2 µm 70%
Wright et al (1982)
0.2-0.4µm 30%
0.4-0.6µm 86%
1

6. 6
Microcosm
Experiments
Intent
• Confirm literature findings and
applicability to the environmental
conditions of Bergen and Thurston Basins
• Experiments conducted:
• Filtration efficacy
• Gradual salinity changes
• Fate of bacteria
• Respiration
• Effect of chlorine
2

7. 7
Filtration
Efficacy
• Ribbed Mussels effectively
filtered bacteria across the
environmental conditions of
Bergen and Thurston Basins
• In a beaker, Ribbed Mussels
shown to filter 56% to 94% of
pathogens
• Low salinity was the only
parameter that temporarily
depressed filtration efficiency
2
(5, 12.5 ppt)
(15, 21, 28 ℃)
(30-35, 55-75, 70+ mm)
(algae and silt levels)
(1, 3, 6 mg/L)
(5, 12.5, 20, 25 ppt)

8. 8
Gradual Salinity
Changes
• Pathogen clearance rates were
temporarily depressed during
low salinity events, but quickly
rebounded as salinity levels
recovered
2

9. 9
• A large fraction of the
pathogens cleared were
removed from the
environment
Fate of
Bacteria
2
To facilitate pseudofeces and
feces collection, ribbed
mussels were suspended
horizontally over a petri dish.

10. 10
• Ribbed Mussels exerted an
oxygen demand of 0.678 mg
O2/hr/g dry tissue
• Based on the mussels’ low
respiration rate, full scale
deployment of Ribbed
Mussels will not adversely
impact the dissolved oxygen
levels in either Bergen or
Thurston Basins
Respiration
2

11. 11
• Activity and survivorship
of juvenile Ribbed
Mussels and were not
adversely impacted when
exposed to acute and
chronic chlorine residuals
Effect of Chlorine on
Juvenile Ribbed Mussels
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
250 100 10 0
(Control)
Percent
Survivorship
at
Day
4 Chlorine Concentration (ppb)
Survivorship of Juvenile Ribbed Mussel
2

12. 12
• Activity and survivorship
larvae were not adversely
impacted when exposed to
acute chlorine residuals;
however chronic exposure
to high chlorine levels
may lower larvae survival
rates
Effect of Chlorine on
Larvae
2
Chlorine Concentration

13. 13
Microcosm
Conclusions
• Mussels effectively filter bacteria across the
environmental conditions of Bergen and Thurston
Basins
• Filtration was only temporarily limited in low
salinity waters, but quickly rebounded as salinity
levels recovered
• A large fraction of the pathogens cleared were
removed from the environment
• Full scale deployment of Ribbed Mussels will not
adversely impact the dissolved oxygen levels in
Jamaica Bay
• Activity and survivorship of juvenile Ribbed
Mussels and larvae were not adversely impacted
when exposed to acute chlorine residuals
2

14. 14
Mesocosm
Experiments
Intent (currently
underway)
• Scale-up from beaker microcosm to a
mesocosm tank to test under flow-
through conditions
Ribbed Mussel holding tank with circulating seawater (top).
Tank setup showing the main, collector, and header tanks (bottom).
3

15. 15
Mesocosm
Experiments
Ribbed Mussel Density:
• Medium Density (720 RM)
• Max Density (1,440 RM)
Bacteria Pulse and Freshwater Input (1,440 RM):
• Bacteria Pulse
• Bacteria Stepped Feed & Freshwater Input
• Spatial Arrangement Variation with Bacteria Step Feed &
Freshwater Input
• Unfiltered seawater, Spatial Arrangement Variation with
Bacteria Step Feed & Freshwater Input
Freshwater input at the head-end of the tank (top).
Close-up of Ribbed Mussels suspended in mesh bags (bottom).
3

16. 16
Sampling
Protocol
• The experiment ran for 4 hours with
samples taken every 20 mins from the front
(influent) and back (effluent) of the tank.
Samples were taken before the bacteria was
added to serve as blanks.
• Samples were analyzed via flow cytometry
and additional samples were analyzed using
standard IDEXX Enterolert techniques used
for measuring Enterococci.
Influent sampling locations and salinity sensor (top).
Effluent sampling locations (bottom).
3

17. 17
In-Situ Pilot
Study Intent
• The next phase will scale up to 75,000 RM
deployed in Bergen or Thurston Basin
• Ongoing discussions with hatcheries to
initiate large scale spawning
• Recent field visit observed Ribbed Mussels
in Bergen Basin
• Structures will be installed to monitor natural
recruitment of mussels
Ribbed mussels (top).
Deployment sites in Bergen Basin under consideration (bottom).
Deployment Sites
Under Consideration
4

18. THANK YOU!